If you are a US citizen or Green Card holder living in the UK, the IRS still wants to hear from you every year — even if you owe nothing. Here is the short, practical version of what to file in 2026 and when.
The deadlines that actually apply to you
- 15 April — standard filing deadline (and US tax payment deadline if you owe).
- 15 June — automatic 2-month extension for Americans abroad. No form needed.
- 15 October — final extended deadline if you file Form 4868 by 15 June.
- 15 December — extra 2-month discretionary extension by written request, granted in limited cases.
- 15 April → 15 October — FBAR (FinCEN 114) deadline, with automatic extension.
What you usually need to file
- Form 1040 — your main return reporting worldwide income.
- Form 2555 — if you claim the Foreign Earned Income Exclusion (~$126,500 for 2026).
- Form 1116 — if you claim Foreign Tax Credits for UK tax paid.
- FinCEN 114 (FBAR) — if your non-US accounts ever exceeded $10,000 aggregate.
- Form 8938 (FATCA) — if your foreign financial assets exceed $200k (single, abroad).
- Form 8621 — for each PFIC you hold (typically UK funds, ISAs holding equities).
Common mistakes we see every April
Filing only in the UK and assuming the US is covered. The two systems are independent — you have to file both.
Forgetting workplace pensions or SIPPs on the FBAR. Most UK pension wrappers count.
Treating an ISA as tax-free for US purposes. The IRS does not recognise the ISA wrapper, and any underlying funds are usually PFICs.